Locator and lock screw



Jill 12, 1949. A. E. HORMAN 2,476,195

LOCATOH AND LOCK SCREW Filed Feb. 5, 1946 INVENTOR P- ALFRED E. HERMAN ATTORNEY Patented July 12, 1949 UNITED STATES PATENT OFFICE 2,476,195 LooA'roR AND LooK soRE'w' Alfred E. Harman; New York; N. Y.

Application February 5, 1946, Serial No. 645,508

quired that the saw or other tool carried by oneof a pair of relatively rotatable members be shifted quickly from one to another angularly related positions and relocated accurately in its reset position. It has been known to provide such machines with some form of bolt or latch carried by one of the rotatable members for engaging in accurately spaced apart recesses in its companion. Such devices have not proven entirely satisfactory in service among other reasons because the vibration to which such machines are subjected tend to loosen the lock and even if the lock were secured in its set position when the machine was new, the eventual wearing away of interfitting parts subsequently renders the locking feature less secure.

The primary object of the invention is to provide an improved form oflock of the type above outlined the bolt element of which can be quickly; released whenever desired as by the turning of the knob of a door; which bolt when shifted into its new position and the lock released will assist in bringing the rotatable parts automatically into an accurately preset relation before the lock canfunction and in which the associated projected bolt will be firmly seated in its associated recess even though the interengaging parts of bolt and recess by a powerful camming action may have worn away in use.

The invention particularly features an arrangement in which the bolt after being initially seated in engagement with any one of the recesses under spring load and fitted more or less snugly into its final locking position may thereafter be quickly cammecl with a powerful mechanical advantage into firm engagement with all of its seat and at the same time to take up any incidental wear between the bolt and its seat or between the elements of the camming mechanism.

Various other objects and advantages of the invention will be in part obvious from an inspection of the accompanying drawings and in part will be more fully set forth in the following particular description of one form of device embodying the invention, and the invention also consists in certain new and novel features of Fig. 1 is a vertical sectional view taken on one side of a pair of rotatable members equipped with a preferred embodiment of the invention shown in axial section taken on the line l -l of Fig; 1 and showing the locator latch locked in its projected operative position; I

Fig. 2 is a horizontal sectional view taken on, the line 2-2 of Fig; 1 with the outer end omitted and with the locator latch in its retracted urilocked position and; l y it Figs. 3 and 4 are each transverse sectional views of the barrel and associated parts-pf the plunger particularly illustrating the arrangement of the lock-groove and takenrespectively on the lines 3 -3 and 4-=4 of Fig.- 1, I I 7 There is disclosed in Figs. 1 and 2 tw o massive machine members Ill and II secured together by" bolt l2 and normally mounted for free rotary movement about the axis of the bolt and restrained from relative movement inall other rections. In-one form of the invention'the inner member I0 is a rotatable machine head and the; other member II is a fixed drum which carries a saw or similar type of woodworking tool not herein illustrated. I y g Theinner member l0 isprovided with aninner cylinder [3 to which is fitted an outer cylinder; [4- in telescopic relation to permit free relative rotation between the two members lfl and II about-the axis of the bolt l2. The cylinder I l is provided on one side thereof with a radially err: tending projection J5 forming a fixed bracket conveniently located at the front of the machine or at any other place for ready access by the operator. The outer portion of the bracket forms a barrel I6 having a cylindrical form of bore l'| open at opposite ends. The outer end of the barrel is-externally threaded as shown at l8 and the outer end of the bore is closed by a cap l9 threaded on to the barrel. I

The locator bolt or plunger 20 is slidably and rotatably mounted in the bore ii and includes a cylinder head 21 adjacent its inner end having a sliding fit in the'bore of the barrel. The outer end of the plunger is reduced from the head and forms a-stem 22 slidably guided in the cap [9: The stem is provided at its outer end with a wheel-dike handle pinned to the stem by a setscrew 24.

H A coilspring' 25 at all times under compression 3 project the locator into the locking position shown in Fig. 1. The bolt locator is defined at its forward end by a frusto-conical nose 26 forming a projection extending axially and forwardly from the head 2 l.

The present disclosure particularly features a peculiar form of groove 21 cut in the perimeter of the head 2|. It consists of a straight portion 28 open at the forward end 29 of the head 2| and extends in the direction of the axis of the locator 20 for a distance slightly longer than the axial length of the nose 26. At its rear end the straight portion of the groove opens into a spiral portion 30 which extends for about 270 as best shown in Fig. 3. It is a feature of this disclosure that the pitch of the spiral groove thus formed in the device illustrated is aboutor the inclination of the spiral to a transverse plane is materially less than forty-five degrees and is about five degrees as shown in Fig. 2. Under these circumstances both ends of the spiral are within a transverse plane having the width of the groove as shown in full and dotted lines in Fig. l.

A set screw 3| is screwed into the side of the barrel and is provided at its inner end with a reduced cylindrical finger 32 at all times located in some part of the groove depending upon the position of the locator. I

The portion of the inner cylinder [3 which rotates in advance sockets of the bore I1 is provided with a plurality of recesses or notches of frusto-conical form and each designed with its larger end outturned to receive the nose 26 of the locator with a snug ground tight fit therein. Usually the cylinder 13 is provided on some exposed part thereof with a scale containing angle graduations to assist the operator in locating the members I and H in whatever angular relation he may desire. In the instant case three such notches are illustrated as shown in Fig. 2, a middle or zero notch 33 and two other sockets on opposite sides thereof and spaced 45 degrees therefrom, one designated as a plus forty-five degree notch 34 and the other designated as a minus forty-five degree notch 35.

In operation and assuming that the nose 26 of the locator 20 is advanced into its locking position engaging say the socket notch 33 and with the finger 32 in the spiral portion 30 of the groove 21 as shown in Fig. 1 and that it is desired to unlock the connection, the operator turns wheel 23 until the finger 32 is at the right end of the straight portion 28 of the slot 27. He knows that he cannot rotate the locator further because finger 32 has reached the end of the spiral portion 33. The operator then pulls the handle 23 axially outward and against the tension of spring 25 until the nose 26 has fully cleared the notch 33. During this time the finger 32 is free to slide in the straight portion 28 of groove 21, or more accurately expressed the relation of finger and groove 28 permits such outward axial movement of the locator. When the locator is free of the notch in which it was located, the operator can turn the inner member ID somewhat and then let go of the wheel 23. The nose or pin 26 rides against the outer surface of the inner cylinder 13 and is held thereto by the spring 25. When the drum of cylinder [3 has been rotated to bring either of the notches 34 or 35 into registry with the locator, its spring pressed nose 26 will jump into the registering notch in spring loaded bearing engagement with its conical seat. This will bring the finger 32 again into the right end of the straight slot portion 28 and to the beginning of the spiral portion. Then with a twist of the handle 23 in the permissible direction the locator nose is more firmly advanced into locked bearing engagement with the nose seat provided by the wall of the notch so engaged. The inner and outer members are thus firmly and securely locked in their new position.

Should it be desired to set the members in any other fixed rotative position defined by the location of any of the other notches, the same operation is practiced.

In case the operator should hold the handle 23 retracted and rotates the member 13 until almost in its desired re-set position the subsequent release of the locator will cause the nose 26 if not exactly coaxial with the selected recess to feel its way into the recess under the load imposed thereon by the spring 25 and this has the effect of adjusting the members automatically into their desired position as the nose of the ocator is forced into engagement with the associated notch.

In general the parts are proportioned so that when the combined bolt and locator has advanced into say a very light spring loaded engagement of the nose 26 in the recess, the pin 32 will have reached the right end of the straight portion 28 of the slot. The operator then forcefully rotates the handle 23 in a clockwise direction as viewed in Figs. 3 and 4. This will have the effect of turning the locator and thus its head 2! acting as a screw in the proper rotative direction to advance the head and with it with a slight rotating twist the nose 26 and thus jam it more forcefully into the recess 33 than when under spring load. The nose will be thus held seated in the recess not by reason of spring pressure but by reason of the low angled cam action between the spiral and the tooth forming stud 3|. It is then seen that every time the nose 26 is thus cammed on to its seat it exerts an action resembling the twisting of a stopper into the throat of a bottle, thus placing the nose under a rotary twisted strain and acting in a tendency to provide a grinding fit between the nose 26 and the conical wall in which it fits.

It has been found that the subsequent vibration and shocks to which such woodworking machines are subjected when in use have had no effect in loosening the cammed or screw locking effect herein featured. It is appreciated that in time the interengaging walls of both the nose and recess wear away but this has no effect on the locking operation as thus described; it simply means that the handle is turned over a few more degrees of turn and the nose advanced a little further into the recess to compensate for any clearance provided by this wear. It is also possible to replace the set screw 3! if necessary to take up for wear.

I claim:

I. The combination with two members mounted for rotary adjustment about a common axis, of means providing a combination locator and lockscrew for the same, said means including two concentric cylinders in telescoping relation, one forming a part of one of the members and the other forming a part of the other member, the inner cylinder provided with a recess of frustoconical form having its larger end at the outer perimeter of the inner cylinder and having some material depth considered axially, the outer cylinder provided with an outwardly projecting extension forming a plunger barrel with a cylindrical form of bore, a cap screwed to the outer end of the barrel to close the bore, a plunger having a cylindrical head slidably guided and 5, rotatably mounted in the bore, saidgulding head provided at its forward end with a frusto-conical nose fashioned to fit in the recess and having a stem guided through the cap and provided at its outer end with a handle, a spring coiled about the stem and at all times bearing at one end on the cap and at its other end on the head in a tendency to cause the nose to bear on the perimeter of the inner cylinder when-displaced from: therec'ess and to project the nose automatically into the recess when in alignment therewith, said head provided in its cylindrical surface with a slot having a straight portion extending from the end provided with the nose a distance less than the distance which the nose must retreat in order to clear the recess, and said slot opening at its rear end into a terminal portion of spiral configuration of less than a complete turn and said barrel-provided with a stud replacably' located therein and having its inner end located in the straight portion of the slot when the nose is retracted axially clear of the recess and disposed in the spiral portion of the slot and under pressure of the spring when the nose is at or adjacent the seat provided therefor by the Wall of therecess.

2. In a device'of the class described, the combination of two cylinders mounted for rotary movement about theircommon axis, the inner cylinder provided with at least one recess of frusto-conical form, the other cylinder provided with a barrel-like extension, a combined bolt and locator guided for axial and rotative movement in said extension and housed therein, the locator provided at its advanced end with a nose of frusto-conical form for fitting in said recess, said locator provided in a side thereof with a slot having a straight portion extending axially thereof at the end adjacent the nose and at the other end terminating in a spiral portion, and said extension provided with a set screw the inner end of which is disposed in said slot and a spring bearing on the locator and biased at all times while the set screw is in the straight portion of the slot to project the nose towards and into the recess and said locator being rotatable when the screw is in the spiral portion of the slot to jam the nose forcefully into any recess in which it may be so located by the spring.

3. The combination of two members mounted for relative rotary movement, one of said members provided with a plurality of recesses each including a conical seat extending radially and the other member having a locator mounted for both axial and rotative movement about its axis and including a nose disposed to enter any one said recess and bear on its seat when in registry therewith, a spring acting at all times on the locator and tending to project the same into any registering recess, a handle for withdrawing the locator from the recess against the resistance of said spring and means including a spiral slot in the locator and a finger fixed to the other member, operating therein and operatively de pendent upon the rotative position of the locator for locking the same in position squeezed between the finger and the portion of the member containing the engaged recess and thus placing the same under an elastic strain when the locator is in operative cammed engagement with an associated recess.

4. In a device of the class described, the combination of two members mounted for relative rotary movement, means for locking the members from rotation, said means including a recess in one of the members, a barrel forming part of the other member and adapted to face the recess, a plunger having a cylindrical head slidably and rotatably mounted in the barrel, said headprovided with a slot having a straight axial- 1:; extending portion adjacent the recess and terminating atv its other end. in a. spiral portion having a pitch materially less than forty-five degrees and having a length between degrees and 360 degrees, and said barrel provided with a stud operating in said slot and located in the straight portion when the plunger is retracted awa from the recess and in the spiral portion when the: plunger is projected into the recess, said straight portion dimensioned to locate the stud at the juncture between the straight and spiral. portion when the locking means are in looking position engaging in the recess.

5. The combination of two members normally mounted for'relative rotary movement about an axis of rotation and adapted to be indexed to each other, locking means for securing the members in accurately preset relation against relative rotary movement, said means including an outwardly facing conical seat in the inner member, a guide barrel forming a part of the other member, a spring loaded combined locator and locking bolt including a cylinder slidable mounted in the barrel, capable of axial and rotative movement therein and provided at one end with a conical nose fashioned and dimensioned to fit in the seat and to bear snugly thereon, said looking bolt including a stem projecting from the cylinder out of the opposite end of the barrel and guided thereby, and provided with a wheellike handle at said opposite end accessible at the end of the barrel, a preloaded spring housed in the barrel, encircling and thus guided on the stem and reacting between the barrel and cylinder for causing the nose to engage the seat and initially to bear resiliently on the seat, and manually actuated camming means reacting between the barrel and cylinder and operating with a mechanical advantage when the handle is rotated for forcing the nose with a twisting motion more firmly onto its seat than when under its initial axially directed spring load.

6. In a device of the class described, the combination of two rugged members one mounted on the other for relative movement about an axis of rotation, the inner member provided on the side facing the outer member with a conical recess backed solidly by the rugged material of the inner member and thus fixed relative to the axis of rotation, the outer member provided with a barrel projecting radially of said axis and having its inner open end at the inner member, a combined locator and locking bolt slidably and rotatively mounted in the barrel for movement to and from the recess, said bolt provided with a nose fashioned to fit snugly in the recess in coaxial relation thereto, a spring housed in the barrel and bearing on the bolt to locate the nose in the recess initially under an axially directed spring imposed load, and camming means reacting between the barrel and the bolt for causing the nose while in its initial spring loaded engagement with its seat additionally to exert a rotary grinding action on the seat and thus to impose a squeeze action between the seat and the nose greater than was imposed by the spring and also to place the portion of the bolt between the camming means and the recess under a powerful compression.

7. In a device of the class described,- the combination of locking means including a bolt guided for axial and rotative movement about its axis, said bolt provided with a slot having a straight portion terminating at one end in a spiral portion of small pitch and having a circular length of more than one hundred and eighty and less than three hundred and sixty degrees, a fixed stud operating in the slot, a spring bearing on the bolt and operating when the stud is in the straight portion to project the bolt in the direction to cause the stud to be located at the juncture of the straight and spiral portion of the slot when the bolt has reached the limit of its spring impelled movement, said juncture providing a stop for limiting the spring pressed advance of the bolt, and manually actuated means operable when the stud is in the spiral portion of the slot for turning the bolt in the direction to cause the spiral portion of the stud to react with a camming effect in the direction to advance the bolt with a rotary movement and axially in the direction of spring load and independently of the spring load.

8. In a device of the class described, the combination of two members mounted for relative rotary movement about an axis of rotation, one member provided with a conical seat fixed relative to said axis and the other member provided 8": with a bolt having a conical nose fashioned to fit said seat, a backing spring acting on the bolt to locate the nose initially in spring loaded hearing engagement with the seat, and manually actuated camming means reacting between the bolt and said other member for forcing the nose on to its seat with a low pitch twist and under a mechanical load more powerful than the load imposed thereon initially by the spring.

ALFRED E. HORMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 572,255 Hall Dec. 1, 1896 610,736 Dietrich Sept. 13, 1898 1,406,103 Tampier Feb. 7, 1922 1,706,331 Steele Mar. 19, 1926 1,710,091 Grimm Apr. 23, 1929 2,072,877 Green Mar. 9, 1937 2,185,814 Kuhn Jan. 2, 1940 FOREIGN PATENTS Number Country Date 124,363 Great Britain Mar. 27, 1919 

